New findings challenge established views on human genome – NHGRI

BETHESDA, Md., Wed., June 13, 2007 – An international research consortium today published a set of papers that promise to reshape our understanding of how the human genome functions. The findings challenge the traditional view of our genetic blueprint as a tidy collection of independent genes, pointing instead to a complex network in which genes, along with regulatory elements and other types of DNA sequences that do not code for proteins, interact in overlapping ways not yet fully understood…

In recent years, researchers have made major strides in using DNA sequence data to identify genes, which are traditionally defined as the parts of the genome that code for proteins. The protein-coding component of these genes makes up just a small fraction of the human genome – 1.5 percent to 2 percent. Evidence exists that other parts of the genome also have important functions…

The collaborative study focused on 44 targets, which together cover about 1 percent of the human genome sequence, or about 30 million DNA base pairs. The targets were strategically selected to provide a representative cross section of the entire human genome. All told, the ENCODE consortium generated more than 200 datasets and analyzed more than 600 million data points…

The ENCODE consortium’s major findings include the discovery that the majority of DNA in the human genome is transcribed into functional molecules, called RNA, and that these transcripts extensively overlap one another. This broad pattern of transcription challenges the long-standing view that the human genome consists of a relatively small set of discrete genes, along with a vast amount of so-called junk DNA that is not biologically active.

The new data indicate the genome contains very little unused sequences and, in fact, is a complex, interwoven network. In this network, genes are just one of many types of DNA sequences that have a functional impact. “Our perspective of transcription and genes may have to evolve,” the researchers state in their Nature paper, noting the network model of the genome “poses some interesting mechanistic questions” that have yet to be answered…